Major updates + Object refactor + new console.log formats for types

• UnexpectedKeyword(Else) bug fixed jasonwilliams#38
• Contributing guide added
• Ability to specify file - Thanks @CallumQuick
• Travis fixes
• Parser Tests - Thanks @Razican
• Migrate to dyn traits - Thanks @Atul9
• Added implementations for Array.prototype: concat(), push(), pop() and join() - Thanks @CallumQuick
• Some clippy Issues fixed - Thanks @Razican
• Objects have been refactored to use structs which are more closely aligned with the specification
• Benchmarks have been added
• String and Array specific console.log formats - Thanks @CallumQuick
• isPropertyKey implementation added - Thanks @KrisChambers
• Unit Tests for Array and Strings - Thanks @GalAster
• typo fix - Thanks @palerdot
• dist cleanup, thanks @zgotsch